Direct current transistor voltage or current regulators



June 2, 1959 G. M. FORD ETAL 2,889,512

DIRECT CURRENT TRANSISTOR VOLTAGE OR CURRENT REGULATORS TEMP. coma 18 INVENTORS.

. FIG- GERALD M. Pom:

B. DALE TAGUE Wmws.

United States Patent DIRECT CURRENT TRANSISTOR VOLTAGE OR 'CURRENT REGULATORS Gerald M. Ford and Byrl Dale Tague, Indianapolis, Ind., assignors to the United States of America as represented by the Secretary of the Navy Application May 12, 1955, Serial No. 508,004

Claims. (Cl. 323-22) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalities thereon or therefor.

This invention relates to direct current voltage and/ or current regulators and more particularly to directcurrent voltage and/ or current regulators utilizing semi-conductor circuits of the series type.

While many direct current voltage regulators of the vacuum tube type and of the mechanical-electrical or carbon pile type are well known and have been successful in operation, these regulators are of considerable weight and size which oftentimes make them objectionable for particular applications. With the coming use of semi-conductor elements these regulators may be reduced in size and weight. Of the known regulators utilizing semi-conductors, commonly known as transistors, transistor shunt regulators and series transistor regulators have been produced and successfully operated. In the present invention a transistor type voltage-current regulating device of the series type has been provided which is believed will considerably improve series type transistor regulators. It is therefore a gcneralobject of this invention to provide a direct current voltage and/ or current regulator utilizing semi-conductorcircuitry of the series type to provide an accurate regulation of the voltage or current to a load in assembled equipment of small size and lightweight.

These and other objects, advantages, features, and uses will become more apparent as the description proceeds when considered along with the accompanying drawings Referring more particularly to Fig. 1, there is 11- lustrated a diagrammatic circuit diagram of a direct current voltage regulator utilizing semi-conductor elements in which the direct current supply enters to the left of the figure and the load is coupled to the output at the right of the figure. The positive input is coupled to a terminal 10, which terminal is coupled to a shunt resistor 11, to the emitter of a p-n-p transistor 12, and also to the emitter of a p-n-p transistor 13. The collector of the transistor 12 is coupled to a terminal 14 while the base of this transistor is coupled through a resistor 15 to the negative input of the circuit. The collector of the transistor 13 is coupled to the base of the transistor 12. Terminal 14 of the collector of transistor 12 is coupled through a current compensating resistor 16 to a terminal 17 thence to the positive side of the load. The shunt resistor 11 is coupled to terminal 14 of the current compensating resistor 16. The terminal 14 of: the collector 'ice of transistor 12 is also coupled through a temperature compensating resistor 18, through fixed resistors 19 and 20, and through a potentiometer 21 in series to the negative conductor to the load. The terminal 17 and a tenninal 22 are coupled through a Zener diode 23 and the terminal 22 is coupled through a fixed resistor 24 to the negative conductor of the system.

The control signal of the regulating device originates from the adjustable tap of the potentiometer 21 providing a sample of the output voltage. This adjustable tap is coupled to the base of a p-n-p transistor 25. The

emitter of the transistor 25 is coupled to the terminal 22 for obtaining a reference voltage from the Zener diode 23 and the collector of transistor 25 is coupled through a resistor 26 to both the base of a n-p-n transistor 27 and a fixed resistor 28 to the negative lead of the system. Resistor 28 causes transistor 25 to have a large residual collector current so that variation of leakage current I with temperature does not affect the circuit adversely. The emitter of the transistor 27 is coupled directly to the negative lead of the system and the collector thereof is coupled through a resistor 29 to the base of transistor 13. The resistors 26 and 29, respectively, protect these transistors from voltage transients by limiting the collector current to a safe value. It may be noted that the transistors 25 and 27 are arranged in such fashion that the emitter of transistor 25 uses a positive voltage whereas the emitter of transistor 27 uses a negative voltage. This coupling arrangement makes it possible to go from the transistor 25 through the transistor 27 to the transistor 13 and obtain the gain desired, without going through a direct current voltage restoration circuit to ob- .tain proper voltage for each transistor.

The capacitors 30, 31, 32 and 33 are coupled in the circuit to prevent oscillations in the system, the capacitors 32 and 33 being in series with the resistors 34 and 35, respectively, in the manner well understood in the art.

In the operation of the voltage regulator device of Fig. 1 let it be assumed for the purpose of example that the output or load voltage has increased. This produces a voltage difference between the terminals 14, 22, represented in Fig. 1 by V and the voltage across the terminal 14 and the adjustable tap of potentiometer 21, represented herein as the voltage V This voltage difference between V, and V produces an increase of emitter-tobase voltage in the transistor 25 resulting in an increase in current from emitter-to-collector which effects an increase in emitter-to-base current of transistor 27. The emitter-to-base current of transistor 27 results in an increase of current between emitter and collector thereof producing an increased emitter-to-base current in the transistor 13. This increase in emitter-to-base current in transistor 13 also produces an increase in current between emitter and collector thereof which produces a voltage rise across the resistor 15. The voltage rise across resistor 15 produces a higher potential on the base of transistor 12 reducing the emitter-to-base current in transistor 12 and consequently decreasing the emitter-to-collector current of this transistor resulting in a voltage reduction to the load. The novel coupling of the transistors 12 and 13 with the emitters of transistors 12 and 13 coupled in common to the positive input and the collector of the transistor 13 coupled to the base of transistor 12 makes it possible to constantly control the emitter-to-collector current in transistor 12 in accordance with the signal on the base of transistor 13. Accordingly, a decrease in output voltage to the load will cause a reduction of current through the base and emitters of the transistors 25 and 27 toproduce a reduction in current from emitter-to-collector in transistor 13 thereby decreasing the voltage across resistor 15 increasing the voltage from emitter-to-base of transistor 12 to cause an increase in.

assas e 7 7 emitter-collector current to raise the output voltage to the load. Coupling the collector of transistor 13 to the base of transistor 12 and thereby to resistor 15, permits use of transistors 13 and 27 in their best operating range by maintaining a high residual collector current'in these transistors so that leakage current 1 variations with temperature do not adversely affect the function of the circuit. The shunt resistor 11 aids in carrying the current to the load and the current compensating resistor 16 compensates for changes in output voltage caused by change of load current. The temperature compensating resistor 18 varies with temperature to compensate for any temperature changes operative on the Zener diode 23 and the transistor 25. The potentiometer 21 may be adjusted to raise or lower the output voltage, as desired. In this manner the voltage at the load is maintained constant for any setting of potentiometer 21 within the conduction limits of the transistor 12 for any change in input voltage, load, or ambient temperature.

Referring more now to Fig. 2 there is illustrated a voltage regulating circuit using semi-conductors or transistors which circuit is similar to the circuit of Fig. l but providing a reverse polarity output wherein the transistors have their emitter and collector circuits reversed and the polarity of the Zener diode reversed. In view of the similarity of these two views, except for these changes, like reference characters will be applied to the elements in this figure, these reference characters being primed. The operation of this reversed polarity regulator is identical to that described for the regulator of Fig. l, and will therefore not be described further herein.

Referring more particularly to Fig. 3 wherein like reference characters are applied to like elements, transistors may be utilized to increase the amplification of the control signal to drive the transistor 12 to an upper conduction limit within the conduction characteristics of this element. This may be accomplished by utilizing atransistor 40 in the circuit between the base of tran sistor 12 and the collector of the transistor 13. In this modification, the base of transistor 12 is coupled to the emitter of the transistor 40, the base of transistor 40 being coupled to the collector of transistor 13 and the collector of transistor 40 being coupled directly to the negative conductor of the system. in this modification the resistor 15 is coupled to the collector of transistor 13 as in Fig. l, but between the collector of this transistor and the base of transistor 49. The control current is introduced to the base of transistor 13 as in Fig. 1.

Referring more particularly to Fig. 4 there is an illustration utilizing two transistors 4i and 41 in series between the base of transistor 12 and the collector of transistor 13 to further increase the amplification and to control the emitter-to-base voltage of transistor 12. The collector of each of the transistors 40 and 41 are coupled to the negative lead of the circuit. More than two transistors, as 40 and 41, may be utilized in the base to collector circuit of transistors 12 and 13 whenever it may be necessary to drive the transistor 12 at a greater conduction rate to the peak of its capacity.

Referring now to Fig. there is illustrated diagrammatically a circuit showing a circuit arrangement for providing current regulation to a load. Like parts to those of Fig. l will bear the same reference character with a double prime. In this circuit the collector of transistor 12 is coupled through a current regulating variable resistor 45 to th e load. The emitter and the collector of the transistor 25 are coupled in the circuit in the same manner as shown in Fig. 1 while the base thereof is couaiaiaaeeuy to the load circuit at the output of the current regulating variable resistor 45.

In the operation of this current regulating device let it be assumed for the purpose of example that the load current decreases. This decrease in load current will produce a decrease in voltage drop across the current e ulatin a ia l r tat 5- Thi lta r p a oss the variable resistor 45 is operative through the transistor 25" by the reference voltage applied through the Zener diode 23" to the emitter of this transistor producing a decrease in the emitter-to-base current and likew se producing a decrease in the emitter-to-collector current of transistor 25". The decrease in emitter-to-collector current of transistor 25 produces a decrease in the emitter-to-base current of transistor 27 consequently producing a decrease in emitter-to-collector current in this transistor. The emitter-to-collector current decrease of transistor 27" produces a. decrease in the emitter-tobase current of transistor 13" and likewise produces a reduction in current between the emitter and collector of this transistor which produces an increase in emitter-to-base current in the series coupled current regulating transistor 12". This increase in emittcrrto-base current of transistor 12 produces an increase in emitter-to-collector current to cause a rise through the current regulating variable resistor 45 to the load. An increase in load current will produce a change in the voltage drop across the current regulating variable resistor 45 to effect the transistors 25", 27", and 13" in the reverse manner to effect a decrease in current from the emitter-to-collcctor in the transistor 12" to lower the current from the emitter-tocollector to the load thereby bringing the load current back to normal. Within the conduction limits of the transistor 12, the current regulating variable resistor 45 may be varied to raise or lower the output current.

While the preferred embodiments shown in the several figures illustrate most of the transistors as being of the p-n-p type and only one transistor being of the n-p-n type, it is to be understood that for particular applications it may be desirable to arrange the transistor circuits with either p-n-p type or n-p-n type transistors in parallel or in complement and in any number to accomplish the desired results. Many modifications and changes may be made in constructional details and features of this invention without departing from the spirit and scope thereof, and we desire to be limited only by the scope of the appended claims.

We claim:

1. A direct-current regulating device in a supply line to a load comprising: a first transistor having its emitter and collector coupled in one supply line conductor and its base coupled through current controlling means to a second supply line conductor; a second transistor having its emitter coupled to the emitter of said first transistor and its collector in coupled association with the base of said first transistor for amplification; a signal circuit including energy sampling means, a third transistor for energy comparison, and fourth transistor coupled in circuit relation with said third transistor for signal amplification and for voltage level and polarity adaptation, said signal circuit coupled in electrical association with the load and supply line and with said first and second transistors to provide control of said first and second transistors substantially unaffected by temperature effects in transistors whereby the energy level in said supply line to a load is regulated to a predetermined value. v

2. direct-current regulating device as set forth in claim 1 wherein said energy sampling means includes diode means coupled in a branch across said supply line to provide a reference energy and includes impedance means coupled to the load to provide an energy proportional to the load energy, and wherein means are coupled across the emitter, collector, and base of said third transistor and to the load for preventing oscillations in said supply line.

3. A direct current regulating device as set forth in claim 2 wherein said third transistor has its emitter and base coupled to said energy sampling means and its collector coupled to the base of the fourth transistor through current controlling means and to said second supply line conductor through impedance means, and

said fourth transistor has a collector coupled to the base of said second transistor through current controlling means and an emitter coupled to said second supply line conductor.

4. A direct-current regulating device as set forth in claim 3 wherein said current controlling means coupling the base of said first transistor to said second supply line conductor are transistors and said current controlling means to the base of said fourth transistor and the current controlling means in the coupling between the collector of said fourth transistor and the base of said second transistor are resistors.

5. A direct-current regulating device as set forth in claim 3 wherein said energy sampling means includes a current regulating resistor coupled serially in said one supply line conductor.

6. A direct-current regulating device in a supply line to a load comprising; a first transistor having its emitter and collector serially coupled in one supply line conductor in parallel with shunt resistor and its base coupled through a resistor to the other supply line conductor; a second transistor having its emitter coupled to the emitter and its collector coupled to the base of said first transistor; an energy sampling means in said supply line conductors; a third transistor having its emitter and base connected to said energy sampling means and its collector connected to the base of a fourth transistor through a current regulating means, the base of said second transistor being coupled to the other supply line conductor through the emitter and collector of said fourth transistor through a current regulating means; and means coupled across the load and across the emitter, collector, and base of said third transistor preventing oscillations in said supply line whereby the energy level in said supply line to a load is regulated to a predetermined value.

7. A direct-current regulating device as set forth in claim 6 wherein said energy sampling means includes a voltage divider across said supply lines to the load and a diode reference means across the output of said first transistor and said other supply line, and said current regulating means are resistors.

8. A direct-current regulating device in a supply line to a load comprising; a first transistor having its emitter and collector serially coupled in one supply line conductor in parallel with a shunt resistor and its base coupled through a resistor to the other supply line conductor; a second transistor having its emitter coupled in common with the emitter of said first transistor and its collector coupled to the base of said first transistor; an energy comparison means in said supply line; a third transistor having its emitter and base coupled to said energy comparison means for producing a signal on its collector in relation to the energy in said supply line to a load; a fourth transistor having its base coupled through a current controlling resistor to the collector of said third transistor and also coupled through a compensating resistor to said other supply line conductor, the base of said second transistor being coupled through a resistor and the emitter and collector of said fourth transistor to said other supply line conductor; and means coupled across the load supply lines and across the emitter, collector, and base of said third transistor preventing oscillations in the supply line and transistors whereby the energy supplied over said supply line for a load is regulated at a constant value.

9. A direct-current regulator device as set forth in claim 8 wherein said energy comparison means includes a current compensating resistor having its output end coupled to a terminal and its input end coupled to the output end of said shunt resistor, a diode and a resistor connected between said terminal and said other supply line conductor, and a potentiometer with a temperature compensating resistor in series connected between the input end of said current regulating resistor and said other supply line conductor, the base of said third transistor being coupled to the movable tap of said potentiometer and the emitter thereof being connected in said connection between said diode and resistor in series therewith whereby the voltage to a load will be maintained constant.

10. A direct-current regulating device in a supply line to a load comprising; a first transistor having its emitter and collector serially coupled in one supply line conductor and its base coupled through a resistor to the other supply line conductor; a second transistor having its emitter coupled in common with the emitter of said first transistor and its collector coupled to the base of said first transistor; an energy comparison means in said supply line including a diode in series with a resistor across the conductors of the supply line and a current regulating variable resistor in series in said one supply line conductor; a third transistor having the base thereof coupled to the output side of said current regulating vari able resistor and the emitter thereof coupled to a junction of said serially arranged diode and resistor for producing a signal on its collector in relation to the energy in said supply line to a load; a fourth transistor having its base coupled through a current controlling resistor to the collector of said third transistor and also coupled through a compensating resistor to said other supply line conductor, the base of said second transistor being coupled through a resistor and the emitter and collector of said fourth transistor to said other supply line conductor; and means coupled across the load supply lines and across the emitter, collector, and base of said third transistor preventing oscillations in the supply line and transistors whereby the direct current supplied to a load is regulated to a constant value.

References Cited in the file of this patent UNITED STATES PATENTS 2,693,568 Chase Nov. 2, 1954 2,693,572 Chase Nov. 2, 1954 2,698,416 Sherr Dec. 28, 1954- 2,716,729 Shockley Aug. 30, 1955 2,751,549 Chase June 19, 1956 

